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CathyVI
Lapis Lazuli | Level 10

Hello,

I am trying to use IPTW but I encountered this warning after running my code. I would like to know what this warning means and how to rectify the warning and have a smooth running code. 

 

/*Log*/

1 OPTIONS NONOTES NOSTIMER NOSOURCE NOSYNTAXCHECK;
72
73 proc logistic data= data1 desc;
74 class sex agerace (ref=first)
75 ALZHDMTE_a (ref=first)
76 AMIE_a (ref=first) ANEMIA_a (ref=first)
77 ATRIALFE_a (ref=first) ASTHMA_a (ref=first)
78 CHFE_a (ref=first) CHRNKDNE_a (ref=first)
79 COPDE_a (ref=first) DIABTESE_a (ref=first)
80 GLAUCMAE_a (ref=first) HIPFRACE_a (ref=first)
81 HYPERL_a (ref=first) HYPERP_a (ref=first)
82 HYPERT_a (ref=first) HYPOTH_a (ref=first)
83 ISCHMCHE_a (ref=first) OSTEOPRE_a (ref=first)
84 RA_OA_E_a (ref=first) STRKTIAE_a (ref=first)
85 cancer_a (ref=first) /param=ref;
86 model case (event='1') = age sex race ALZHDMTE_a
87 AMIE_a ANEMIA_a ATRIALFE_a ASTHMA_a CHFE_a
88 CHRNKDNE_a COPDE_a DIABTESE_a GLAUCMAE_a HIPFRACE_a
89 HYPERL_a HYPERP_a HYPERT_a HYPOTH_a ISCHMCHE_a
90 OSTEOPRE_a RA_OA_E_a STRKTIAE_a cancer_a / link=logit rsquare;
91 output out=data1_PS p=A1_C xbeta=logit_ps;
92 run;
 
NOTE: PROC LOGISTIC is modeling the probability that case=1.
WARNING: There is possibly a quasi-complete separation of data points. The maximum likelihood estimate may not exist.
WARNING: The LOGISTIC procedure continues in spite of the above warning. Results shown are based on the last maximum likelihood
iteration. Validity of the model fit is questionable.
NOTE: There were 1234567 observations read from the data set WORK.data1.
 

 

1 REPLY 1
ballardw
Super User

It is caused by your data. Fix is problematic.

 

You can read this link for some ideas that may apply to your data: https://stats.oarc.ucla.edu/other/mult-pkg/faq/general/faqwhat-is-complete-or-quasi-complete-separat...

 

Note that is the first return from my internet search of " quasi-complete separation of data points"

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